A Little Logic
by CoconutsAndJelly
Summary: 221b Baker Street just got a little bit more interesting - if you could imagine that.
1. Chapter One

"Er, where am I?" she muttered to herself, looking up from the property details to the busy road she was on.

She'd crossed Dorset Square and she knew she'd gone down Glentworth Street, but for the life of her she couldn't find where she was going. From where she was standing, she could see a jeering sign diverging only that she was on Siddons Lane, but that was no use.

'Melcombe Street, am I going there?' she huffed, walking towards the crossroads.

* * *

"At some point Lestrade, you're going to give up; it's quite obvious I'm not on drugs."

"Fortunately, you have no proof of that, Sherlock," he countered, picking up a cushion from the sofa and ignoring Sherlock's huff as he was forced to sit up, "So I'm free to search the entire house until I'm happy you're clean."

"Mrs. Hudson would not allow two drug-addled fiends into her home."

"Of course not Sherlock dear, but I would like it if you'd stop shooting the wall," she said, "The bullet holes are quite expensive to fix."

* * *

Hermione frowned as she finally reached the long row of bricked townhouses of Baker street. There were police cars parked all along the road and the door of number 221 looked as though it'd been kicked in. She wasn't sure whether to enter or not - she most certainly did not want to lodge with criminals - but she was sure the kind woman she'd spoken to on the phone was safe.

"Well on the bright side, if they are criminals, they're being detained," she told herself, pushing open the battered black door.

She could hear loud voices coming from the first floor, mostly from a east Londoner, but not the sweet landlady she'd spoken to on the phone.

* * *

"Lestrade, there's a head in the fridge."

"Anderson, do not touch it!" Sherlock shouted, walking over the table to the kitchen where the team was crowding round the fridge, "It's an experiment of mine and we all know you don't have enough intelligence to not ruin it entirely."

"You do know we're in the homicide unit, don't you?"

Whatever comeback Sherlock was planning on saying was interrupted by a shy knock on the door. Everyone in the room turned to watch as Mrs Hudson stood from the sofa, "Look what you've all done now. Scare the girl half to death, why don't you."

"Girl?" Sherlock asked, but Mrs Hudson ignored him and instead went to the door. Him, John, Lestrade and Anderson stopped as the rest of the team continued to search.

"Oh dearie, it's so lovely to meet you! Now aren't you pretty," she cooed, making the others even more curious as they waited for this mysterious woman to come inside.

"Who would come to visit this psychopath?" Anderson asked. John rolled his eyes at the inevitable reply.

"I am a sociopath, not a psychopath. Do your research, for god sakes."

"Come on in then dear," Mrs Hudson said, ushering the visitor through the door, "We're just having a little drugs raid, nothing to worry much about."

"Oh, okay," they heard a hesitant voice Sherlock instantly recognised as a Surrey accent.

She had lightly tanned skin which screamed holidays in France and the high cheekbones and soft jaw line she had were definitely of British origin, but her almond-shaped eyes and the silky, spiraling honey tresses that fell to her shoulders in waves that could only be natural told him she probably had ancestors from elsewhere in Europe – perhaps France? She certainly seemed from somewhere other than here, though Sherlock thought her to be younger than either him or John, at least by five years. She was wrapped in a warm winter coat - telling him she had just moved away from somewhere cold as the weather outside was quite warm for England - with a thick scarf wound around her neck and jeans underneath by the looks of things. What didn't make sense was the lack of flush in her face. She could only have been this cool if she'd managed to appear in London from thin air. But how?

"Now dear, you mustn't think this happens all the time," Mrs Hudson said smiling, bringing her into the room, "Things will calm down but my other lodgers to tend to get into some interesting situations, you see, so there will be some times we have drugs raids and they're on quite good terms with the police."

"She's quite fit," Anderson whispered. John closed his eyes and sighed as Sherlock turned to speak, but for the second time that day he was interrupted.

"Well then you must come back when I'm thoroughly inebriated, perhaps then I'll return your sentiments," the girl rolled her eyes, smiling as Mrs Hudson followed her inside.

Witty _and_ mysterious, how intriguing.

"No, unfortunately nobody will ever find Anderson even remotely attractive," Sherlock said, smirking at the outraged look on his face.

"I don't know, he's doing alright for somebody who's married and having an affair," she smiled, looking the man up and down, "You do know she's gotten engaged now, don't you?"

"Oh jesus, another one," Anderson groaned, "How do you know she's engaged then?"

"There's a slight nick under your ear."

"What? She told me that was a promise ring!"

"Greg Lestrade," a tall, handsome man introduced himself, "I promise, not everyone in the unit is so moronic."

Hermione laughed, admiring his strong jaw line and arms, "Nice to meet you, I'm Hermione, Hermione Granger."

"What a lovely name," he smiled, "Very unusual."

"Stop flirting, Lestrade, she's almost half your age," Sherlock droned, whacking away an officer who was reaching over to a steaming beaker full of a suspicious red liquid.

"Oh, I don't know," Hermione said, looking over to the man who'd interrupted, "I've always enjoyed the company of an older man. All that experience."

"I'd say you've had one or two older men by the looks of you," he smirked again, looking her up and down.

"And by the looks of you, you haven't had much of anything," she grinned, "An older man with no experience. What a waste."

"No, but running after Lestrade is a waste; he's still pining over his ex."

"But she cheated on him with a PE teacher?" she said confusedly, turning to the man in question with a grin on her face, "You could do so much better by the way."

"Sherlock," he said, grabbing her attention back.

"What?"

"My name, little girl, is Sherlock Holmes."

"And I'm John," another man piped up, "Nice to meet you."

"I'm not little," she ground out despite her small stature in comparison to the large men she stood before.

"Well Mrs Hudson, do you plan to explain what this _charming_ little girl is doing in our flat?" Sherlock asked, ignoring her remark smugly.

"Well dearie, she's your new roommate," she smiled, "Would you like a cup of tea?"


	2. Chapter Two

**Lady'-'Starry'-'Night**: Thanks so much! I worry about the first chapter.

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* * *

It had been a week, and not much had been said between the detective duo and the newest lodger in 221b Baker Street.

Hermione had been very busy setting up her new shop down the road and there'd been an influx of cases for her sleuths apparently. It seemed almost like they were avoiding her, but that couldn't be right, could it?

Mrs Hudson had been kind enough to introduce her to life in London gently - having just come from two years working in Hogsmeade in Flourish and Blotts, the big city lifestyle was completely opposite to her usual weekends spent in her flat above the shop with her favourite book in hand.

Now she saw a different person everyday in her new job. The weather was so variable in London you never know whether it will be hot or cold, rainy or sunny from one day to the next, unlike in Scotland where it was always cold and never rained. London was everything Hogsmeade wasn't: busy, crowded, huge, difficult to get around and expensive.

The only time it got like that in Flourish and Blotts was when there was a visit from Hogwarts. Ron had grumbled, telling her it was cool, cosmopolitan and current and possibly the worst place for a 'homely' girl like her to move to, but so far, she'd only seen snug little cafés, delightful corner shops and cosy little pubs she'd pass on her way to work. Besides, she didn't want to get in the way of him and Luna now they were married.

She was happy here; she was settled. Plus, the other tenants seemed much too busy to notice all the magic crackling around in 221b.

* * *

Sherlock sighed as he heard the door of their flat slam closed again.

Each day, he woke on his sofa - neglecting the bed he was 'supposed' to sleep in, according to John, for a much more comfy place to sleep - and waited, eyes closed on his sofa for her to leave.

"John, she's gone," he called out.

They both got up, John coming out of his bedroom on Sherlock's command.

"I don't understand," he sighed, "Why are we hiding from her again?"

"She's new, John," he said as if it was obvious, "I don't like people in general, therefore why wouldn't I be opposed to her being here."

"She seems nice," he countered, walking over to the kitchen where a note was attached to a plate of pancakes, "Look she even made breakfast."

"John it'll be cold by now, she hasn't been in that kitchen for ten minutes," Sherlock rolled his eyes arriving in the kitchen, "What are you doing?"

"There still warm, so I'm eating them. We never get breakfast when we're on cases."

"But how?"

Instead of answering, John just shoved a post-it in his hand and started lavishing a pancake with sugar and lemon and taking a bite, "Yummy."

_John, _

_I don't know whether Sherlock __will be up yet, but I just thought __I'd do something nice as we haven't __seen much of each other yet._

_I made some pancakes and put out some of the regular toppings - sorry we don't have any chocolate sauce! It should still be warm by the time you get to it, I am magic like that,_

_Hermione._

God, is that woman ever going to make sense?

"Sorry John, we don't have time for this, thing. though you can thank the little girl later," Sherlock sighed, looking at his phone, "Lestrade has a case he needs help with."

"Where this time?"

"Ivor place, apparently."

"That's just five minutes walk from here," John said, finishing off his breakfast, "Are we walking?"

"John it's a murder, this is not the time for an early morning stroll."

"Alright, just thought I'd save the world some pollution, the body will still be dead when we get there," he said, grabbing his coat.

"Yes, but knowing Lestrade he's brought along Anderson, and the evidence will be buggered if we waste any more time."

* * *

"Oh, you're the girl who lives with Sherlock and John. Hermione isn't it?" Lestrade smiled, looking over to the woman he'd met earlier that week as she nodded, "Didn't expect to see you at a crime scene."

"Well neither did I, really," she said, looking awkwardly down to the person lying in front of her till in a pool of his own blood, "I'm not too sure why someone's been killed in my store. I mean, it's just a little book shop."

"I saw," he laughed, glancing around the room, "A Novel Idea, cute."

"Yeah, my friend Harry came up with it," she said, following his eyes.

Thousands of items were crammed onto the shelves that surrounded the little till, hosting everything from out-of-print dictionaries and long-forgotten bestsellers to leather bound collections of Shakespeare and popular children's books. It hadn't taken her long for her to sort the books she did have.

Hermione had always felt at home in that environment, a kind of paper mausoleum, piles of discarded books handy to flip through whenever the shop was empty and breathing in her favourite old dusty book smell as she served.

"So, how come you haven't started investigating yet?"

"We're waiting for Sherlock," he answered looking at his phone.

"Oh, how come?" she asked, intrigued, "I thought the stupid man said he was a sociopath."

"He's only an apathetic sociopath; he'd kill you if he cared enough to," he told her; she laughed at his dismissal, "He and John are our consultant detectives, but they do private work mostly."

"Oh, interesting," she smiled, "So you're with the police then?"

"I'm a DI with the forensics team, but we seem to specialise in murder," he chuckled.

"Oh, looks like he's here," Hermione told him, pointing to the window where a black cab rolling up to the bookshop turned crime scene, "Hopefully I'm not implicated in this."

"You won't be, I assure you," he soothed her, "We know you only found the body."

The two strolled into the room, the little bell above the door ringing as Sherlock swung the door open, John following.

"Detective, I think I've found some evidence," Anderson said, coming over to them.

"Thank you, Anderson. We're all refreshed and challenged by your uniquely moronic point of view. Now leave," Sherlock said, not even looking his way.

"Hermione, nice to see you," John said, waving to her.

"'lo. Did you get your pancakes alright?"

"I had one, but then this case came up so we had to leave them," he informed her, his personality reminding her of Harry, "Sorry, we can heat them up when we get back."

"There's another one you can't have," Sherlock interjected.

"Why? He's most certainly not gay," she said, winking at John who seemed a bit bewildered but managed to whisper finally, "Don't worry 'bout them, I can have them when I get back; doubt I'll be doing much work here anyway today. It's such a tragedy."

"They'll be freezing, though," John said confusedly.

"No, I mean, I'll warm them up," she muttered, her arm subconsciously feeling her arm where her wand was kept.

"Liar."

"Sherlock," John admonished him, "Don't."

"She's lying and she's at a crime scene John," he replied, staring intently at her, "Little girl's my domain now."

"I'm not little and I'm not lying," she gritted out, folding her arms, almost tempted to stomp her foot.

"You are such a little girl," he chuckled, "A clever little girl no doubt, but still little."

"Is that why you were perving on me this morning pretending to be asleep? Like a challenge?"

"It's only perverted if you really are a little girl," he smirked.

"Guys, there's kind of a dead body to be attended to," John waded in, only to be ignored again.

"I am not a little girl, Holmes," she ground out, looking up at him.

"No, you're a little girl with a bookshop, a dead body and a secret room behind your bookshelf," he said, walking closer to her, "The question is, what on that list is connected."

"Sherlock, she's obviously upset, just leave her be," Lestrade said, placing his hand on her shoulder, "We've got a job to do."

"Oh, that?" he said, pointing to the dead body they'd neglected to investigate, "Simple, the butcher across the road."

"What? How did you... you haven't even looked at it!"

"Show off," John muttered, getting a smile from Hermione who he grinned back to, "Finally someone agrees."

"Please, the only person on this street with the equipment to cause that much blood on a body is across the street. The chemist next door would've drugged him and poison is usually the weapon of choice for cafés like the one on other side of her - that's where he got his lunch. He was a regular in all four shops."

"You sure?"

"Sorry, since when was I on the same level as your goldfish?"

"Just checking," Lestrade said calmly, holding his hands up, "Got the motive?"

"Gay lover who cheated on him," he said, before smirking, "Hey look Anderson, someone who's knees match Sally's."

"I won't even ask," he said, shaking his head and walking to his team to debrief.

"Why aren't you scared?"

"Sherlock, just leave it," John groaned, looking apologetically to her.

"Any normal little girl would be terrified by the sight of a little blood, never mind a whole dead body, but you seem perfectly at ease. Making conversation, flirting with a DI, arguing with me," he paused, "You've seen more than your fair share of dead bodies."

"Soldier to soldier, John, please stop him," she frowned, looking down and away from Sherlock's beady eye, "Skeletons found at war are almost always best left in the proverbial closet."

"Fine, but I will figure you out, Hermione Granger."

"Hermione, we're going to need to clear out in here," Lestrade said, coming over to her, "It'll be best if you just got out of the way for now. Go have some rest, get your mind off this mess."

"Thank you, detective inspector," she said, "Send the family my best, if you will. John, perhaps I'll see you when we get back."

"Yeah, maybe," he nodded, moving out of the way for her to go through.

"Holmes," she acknowledged, before leaving the two in the shop. Sherlock groaned, rubbing his hands against his face.

"She's interesting."

"She's a manipulative bitch," Sherlock countered angrily, "Did you not see the glint in her eyes."

"How are you?" John asked.

"Ever had a day where you want to set someone's face on fire and put it out with the sharp end of a fork?"

"Should I get Mycroft?"

"I want information, John, lots of information."

"Mycroft it is."


	3. Chapter Three

**kylynnjen** & **kingdommast**: Well you guys are in for a treat then because there's a world of Mycroft in this. Him and Lestrade are my favourite characters. Thanks for the review! xxx

**Keira-House M.D** & **NorthernLights25** & **Kithic** & **Huge potter fan** & **sethiel** & **Lfagundes** & **UbholySpectacle **&** Marion Hood **& **Sarah** & **Whiskey-eyes **& **Booklover9477** & **leeeila** & **AurorMartinez23 **& **silver-eyedLadyofDarkness**: Sorry to lump you all together, but I just wanted to thank you for all your kind words! So... thanks! xxx (times thirteen)

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**Thanks for all the reviews; I hope you like this chapter.**

* * *

"You are such a show off!"

She giggled at the disembodied voice's reply, "What, exactly, do you mean?"

"Well your boss usually sends a _car_, not a SWOT team," she retorted, folding her arms and leaning back into the cold metal chair of the colourless room, "What are you playing at?"

"Nothing, I assure you."

"Oh you lying bastard," she smirked as she raised her eyes to her framed reflection where the man she knew was grinning right back at her stood, "Look, this isn't some 'my organised criminal underworld is better that your organised criminal underworld' thing, is it?"

"I really have no idea what-"

"Because if so, one _should_ remember who exactly sweet talked an entire network of active, high-risk dark criminals into consorting with them and eradicating a threat to both their world and yours."

"Oh please, everyone but the boss knew you were cavorting with your co-conspirator."

"Ooh, alliteration," she rolled her eyes, "Someone bringing out the big guns."

"He wasn't worth almost wrecking a years worth of work for, well-"

"A quick shag? Oh I'd say he was; it was fabulous," she grinned, dragging out her last word.

"Please dear, not in present company."

"I'm willing to bet your completely alone in there," she said.

"Really?" his voice perked up from his usual boring tone, "How much?"

"How about those Chinese missile launch codes you've been gagging for these past few weeks?" she asked, winking, "I may even be able to access their data banks... if you beg, that is."

"How vulgar, no man would ever stoop so low as to beg an inferior employee. You are, as usual, completely inaccurate however," he countered, "The British government are no longer concerned with that."

"Oh so that's why Kingsley's been getting special visits from your more _specialised_ agents. You do know he's married, right? Sex is probably the one thing he's not gagging for."

"Come on, we're not here to talk about records I've had access to since before they were written," he said, returning to his drone again, his voice telling her he was getting annoyed.

'_Best leave off,_' she thought, the bright smile spread across straightening out.

"So, Mr Wolf," she said, leaning onto the reflective desk, "What is is that you want?"

"Progress report," he demanded, his tone clipped.

"Oh dear, that voice could be so much sweeter," she sighed, resting her head on her hand, "And did your mother ever teach you manners?"

"Please, tell me, how has your progress been?" he said, the audible grinding of his teeth coming through the speaker.

"You were right," she said, smiling genuinely, "He bought it."

"Good."

"It was genius. I never would've thought of that. Though remembering all that information about those nice policemen was boring."

"Well Granger, get this right and we could be promoting you."

"I know, I know. It is cute, though," she chuckled, "To watch a man that age act like a petulant child when I matched him at his little guessing game."

"Well, that's Sherlock for you," he muttered, "I do believe he wanted to be a pirate when he was older - god knows why," There was a pause as the elder Holmes thought, "How about the murder I set up?"

"He liked it, I think. Worked it out easily enough," she told him, relaxing against the chair, "He most certainly does not like me, though."

"But he's not suspicious."

"He is."

His words were barely formed before she interrupted him, "Look, he just knows about the door to the base in my shop."

"_My_ shop? You better not get too attached to that place, you're not there for the books," he warned.

"But there so pretty!" she whined mockingly, chuckling at the scoff she heard over the intercom, "It's like a dream job."

"Sort it out, Granger."

"I'll clear it out tomorrow."

"And the boyfriend?"

"Jim's fine thanks," she smiled.

* * *

"Regular girl?"

"He says she's from Surrey-"

"I was right."

They'd been siting there for hours, and frankly, John was confused. No way did Sherlock care about anyone other than himself, especially a girl he barely knew and didn't like. It'd been weird, seeing him bitch like a whingey little girl trying to hide a crush from her mates about Hermione. He'd talked about how stupid her bushy (though John had insisted on him saying curly, not that he'd been listening in the first place) brown hair was, how annoying her smug voice was, how she wasn't even intelligent, just lucky. Yes, John had to admit there seemed to be a hint of a smirk on her face just before she'd left the crime scene - and they hadn't seen her in the three days hence - but that was no reason for him to go full out Regina George, as Mrs Hudson had said.

John rolled his eyes before continuing, "Her parents were dentists and she grew up like any other child."

"Education?"

"Primary school, high school then sixth form," John said, sitting across from his best friend, "Nothing out of the ordinary."

"No university?"

"No university."

"She's smart... why no university?"

"Parents couldn't support her?"

"Dentists, John. You're a doctor, you should know that you'd be able to send your children to university comfortably - that is, if you manage to ensnare a woman somehow."

"Hey! If anything, it's you keeping ladies away."

"I'm a delight," Sherlock replied, face straight, "You should know that, John; you spend enough time with me."

"Too bloody much, if you ask me," he muttered, ignoring his friend's raised eyebrows.

"Any other ideas?"

John sighed as Sherlock ran his hand through his mussed hair again. He'd been doing it repeatedly since he'd boy-ed up and texted Mycroft about getting information on her. John knew there was no way of getting him to shut up apart from a good, dirty murder.

"Do we not have any other cases? We've been really quiet lately," he asked, a hint of desperation seeping into his voice, "Lestrade not sent anything?"

"John, I know what avoidance tactics are," Sherlock said, sitting up on his sofa.

"Please Sherlock, you're acting ridiculous! What has this one girl got that all the others who want your attention haven't?"

"Secrets, John," he said, "Hermione Granger isn't normal and she isn't good. Now what else did Mycroft say?"

"She owns a bookshop-"

Sherlock rolled his eyes, "Information we don't already know."

"Okay, she's got no other immediate family, apart from one godson she sees in passing, and a boyfriend."

"Boyfriend?"

"Yep, a James Malfoy."

"Malfoy? That sounds made up. Got any photos?"

"Er, there's one attachment, just give me a second."

Sherlock waited the one second John had told him to, before snatching the phone and scrolling to where the picture was.

"Oh."

"What? Do you know him?"

"We both know him," Sherlock scowled, before shoving the phone into John's hand and stalking into his room.

"Can't be that bad," John sighed, turning the phone to see the photo. There, on his screen, stood the man they'd come to know through perhaps the most unpredictable of circumstances. Schoenberg's violin concerto begun from behind Sherlock's room and John couldn't help but think Sherlock had it right as he stared, bewildered, at the smiling face of Jim Moriarty, walking hand in hand down Baker Street with their newest female roommate.

* * *

Thank you for reading! I hope you enjoyed and are willing to come back for my newest chapter when it finally hit's your screens. :)

Tell me all your thoughts about what's happened, our little romantic revelation and what you think/hope will happen next. Thanks to all my reviewers; you're brilliant!

Love, Em.


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